Sintered bodies of aluminum titanate have low coefficient of thermal expansion and high corrosion resistance. They are known as heat-resistant materials which exhibit low wettability with slag, excellent corrosion resistance, spalling resistance and other excellent properties when used as materials of, for example, containers, ladles, gutters, etc., for molten metals of aluminum, aluminum alloy, ferroalloy and the like. However, the sintered bodies of aluminum titanate, whose crystal grains constituting the sintered bodies are anisotropic, tend to suffer the following disadvantages: displacement at the crystal grain boundaries caused by stress due to the anisotropy of thermal expansion coefficient when heated or cooled; and formation of micro cracks and apertures which may lead to lowered mechanical strength.
Hence, conventional sintered bodies of aluminum titanate have insufficient strength, and can not exhibit sufficient durability particularly when high temperatures and heavy loads are applied thereto.
In addition, aluminum titanate is unstable at a temperature of 1280° C. or below. It tends to decompose into TiO2 and Al2O3 when it is used in a temperature range of about 800 to 1280° C., and therefore is difficult to be used continuously in this temperature range.
To improve the sinterability of aluminum titanate and inhibit thermal decomposition, additives such as silicon dioxide are mixed with raw materials prior to sintering. In this case, however, the refractoriness of the resulting sintered bodies tends to be lowered. For this reason, it has been impossible to obtain a sintered body of aluminum titanate that has refractoriness so as to be usable at a temperature as high as about 1400° C. or higher and also has high mechanical strength.